NbSe2

Purpose: We investigated the interaction of O and O2 on monolayer Niobium Diselenide (NbSe2) to provide theoretical predictions about the electronic properties of the complexes using First principles calculations in Quantum Espresso 6.7. As known, considering impurities in pristine nanomaterials like NbSe2 is very important as it can alter some of its properties. Method: In this paper, we performed some topological analyses on the electronic densities and electronic structures calculations to O- and O2-NbSe2 complexes. Charge Density Difference (CDD) and Bader charge analysis reveal that O and O2 acted as oxidizing agents and accumulated electronic charges from the NbSe2. Results: The electronic properties calculations of the complexes showed that the metallic behavior of NbSe2 is preserved after O and O2 adsorption. Calculations of the net charge transfer revealed that the atomic and molecular oxygen has accumulated electronic charges while the NbSe2 has depleted electronic charges. These results showed the possibility of tailoring the electronic properties of NbSe2. Conclusion: The interaction of O and O2 with the monolayer NbSe2 caused charge redistributions while maintaining the metallicity of the NbSe2. In all circumstances, the results are consistent with the established works which show the possibility of modifying the electronic properties of NbSe2 that could open some potential applications in nanotechnology and other nanoelectronics-related devices.

Published in: "arXiv Material Science".

Monolayer NbSe2 is a metallic two-dimensional (2D) transition-metal dichalcogenide material. Owing to the lattice structure and the strong atomic spin-orbit coupling (SOC) field, monolayer NbSe2 possesses Ising-type SOC which acts as effective Zeeman field, leading to the unconventional topological spin properties. In this paper, we numerically calculate spin-dependent optical conductivity of monolayer NbSe2 using Kubo formula based on an effective tight-binding model which includes $d_{z^2}$, $d_{x^2-y^2}$ and $d_{xy}$ orbitals of Nb atom. Numerical calculation indicates that the up- and down-spin have opposite sign of Hall current, so the pure spin Hall current can be generated in monolayer NbSe2 under light irradiation, owing to the topological nature of monolayer NbSe2, i.e., finite spin Berry curvature. The spin Hall angle is also evaluated. The optical induced spin Hall current can be enhanced by the electron doping and persists even at room temperature. Our results will serve to design opt-spintronics devices such as spin current harvesting by light irradiation on the basis of 2D materials.

Published in: "arXiv Material Science".